The invention relates to rotary internal combustion engines of the type disclosed in prior U.S. Pat. No. 2,988,065 granted on June 13, 1961 on an invention of Wankel et al, and particularly to such an engine designed for operation as a stratified charge engine. Prior stratified charge rotary combustion engines of this type are disclosed in U.S. Pat. Nos. 3,246,636 granted on Apr. 19, 1966 on an invention of Bentele and 3,698,364 granted on Oct. 17, 1972 on an invention of Jones and in co-pending U.S. application, Ser. No. 424,056 filed on Dec. 12, 1973, and now U.S. Pat. No. 3,894,518 on an invention of Gavrun et al.
In rotary engines of the type described in the aforementioned patents and patent application, each engine working chamber, at the time of ignition, has a shape which is relatively long and is quite narrow, particularly at its leading and trailing ends. As a result, combustion of any fuel in the leading and trailing ends of these working chambers tends to be chilled by the adjacent walls of the engine housing and engine rotor thereby resulting in inefficient combustion and in the engine exhaust including unburnt fuel.